Vibration-minimizing magnetic card reader

Abstract

A reader-writer for magnetic cards substantially reduces "jitter" or chattering vibrations which otherwise imperil the accuracy of the read-write functions. The read-write head is itself mounted rigidly for operating while the magnetic card passes along a planar tray surface. A soft rubber anvil roll is mounted directly opposite, for free idling rotation on the same shaft which impels a rubber driving wheel. In contrast with conventional constructions using a spring-mounted head or anvil, the present rigidly mounted head in combination with the free idling soft anvil roll avoids the generation of, and damps out, vibrations, which otherwise might follow from exciting forces such as irregularities in driving friction. The greatly improved accuracy makes feasible the use of debit cards, and has unexpectedly reduced head wear.

We claim: 
     
       1. A vibration-minimizing card reader for magnetically encoded cards, comprising a planar card tray adapted to support a magnetically encoded card for movement in a longitudinal delivery path therealong, a magnetic reader head presented rigidly along said path and at substantially the level of said planar card tray, electronic circuitry so connected to said reader head as to verify data encoded longitudinally on such cards and, on such verification, to direct the performance of an electronic command, a transverse shaft in longitudinal registration with said reader head and having an axis at a level fixedly spaced from the plane of said card delivery tray, a radially deflectable rubber-like anvil roll so mounted on said shaft, immediately opposite to said reader head, as to permit idling rotation movements of the roll relative to the shaft, and means to engage and drive such encoded card along the longitudinal delivery path of said planar card tray, said means to engage and drive including a motor, means to engage it to said transverse shaft, a driving roll mounted on and secured to said shaft spaced axially from said anvil roll, and a driven roll projecting upward through and beyond the level of said planar card tray, said driving roll being of smaller diameter than and being characterized by greater resistance to deflection than said anvil roll, whereby the deflectance and damping characteristics of the rubber-like anvil roll, and its idling rotational movements, avoid vibrations in card reading and writing. 
     
     
       2. A vibration-minimizing card reader as defined in claim 1, wherein the delivery path of the planar card tray is substantially along an upper surface of said card tray and is horizontal, and the axis of the transverse shaft is above the plane of said card delivery tray, and the reader head extends through an aperture in the card tray to the plane of such path. 
     
     
       3. A vibration-minimizing card reader as defined in claim 1, together with optical sensor means, positioned along the planar card tray at either side of the reader-writer head, to start and stop the motor responsive to the position of an encoded card along such longitudinal delivery path. 
     
     
       4. Debit card reader-writer apparatus, comprising a vibration-minimizing magnetic card reader as defined in claim 1, wherein said electronic circuitry includes means to store encoded information read from such card, and means effective on delivering an electrical command, to so modify the encoded information as to reflect the delivery of such command, to energize the motor to drive such card in reverse direction, to cause the reader head to write the modified information on the card as it proceeds in such reverse direction, and to deliver the card from the reader. 
     
     
       5. A vibration-minimizing card reader as defined in claim 1, wherein the card tray includes side guide means for delimiting such path and said transverse shaft is mounted on said side guide means, outwardly of said anvil roll and said driving roll.